Big power storage potential

New research by MIT scientists, led by associate professor of mechanical engineering Carol Livermore, suggests that carbon nanotubes, tube-shaped molecules of pure carbon, could be formed into tiny springs capable of storing as much energy, pound for pound, as state-of-the-art lithium-ion batteries - and more than 1,000 times as much as steel springs - and potentially do so more durably and reliably.

Ultimately, such springs might be used for such applications as an emergency backup power supply or alarm system that can be left in place for many years without losing its "charge," portable mechanical tools like leaf blowers that work without the noise and fumes of small gasoline engines, or devices to be sent down oil wells or into other harsh environments where the performance of ordinary batteries would be degraded by the extremes of temperature.

Livermore and her team did a combination of mathematical analysis and small-scale laboratory testing to determine the potential of carbon nanotubes to be used as springs for energy storage.

Livermore says that to create devices that come close to achieving the theoretically possible high energy density of the material will require plenty of additional basic research, followed by engineering work. Specifically, the initial lab tests used long fibers of individual carbon nanotubes joined end-to-end, but creating a practical energy storage device will require assembling nanotubes into longer, thicker fibers without losing their key advantages.